Agent Orange exposure tied to lethal prostate cancer

Exposure to Agent Orange is linked to lethal forms of prostate cancer among United States veterans, according to a study.

The findings suggest Agent Orange exposure history should be incorporated into prostate screening decisions for veterans, researchers reported.

The herbicide Agent Orange was heavily used during the Vietnam War era and often was contaminated with dioxin, a dangerous toxin and potential carcinogen, according to background information in the study, which was published May 13 on the website of the journal Cancer. Prior research suggests exposure to Agent Orange may increase menís risk of developing prostate cancer, but whether it specifically increases their risk of developing lethal forms of the disease has been unclear.

"This is an important distinction as the majority of prostate cancer cases are non-lethal and thus do not necessarily require detection or therapy," Mark Garzotto, MD, of the Portland Veterans Administration Medical Center and Oregon Health & Science University, said in a news release. "Having a means of specifically detecting life-threatening cancer would improve the effectiveness of screening and treatment of prostate cancer."

To look for a link between Agent Orange exposure and high-grade prostate cancer, Nathan Ansbaugh, MPH, designed and conducted analyses on a group of 2,720 U.S. veterans who were referred by multiple providers for initial prostate biopsy. Biopsy results and clinical information were compiled for analysis by Garzotto, the studyís principal investigator.

Prostate cancer was diagnosed in 896 (32.9%) of the veterans; 459 (16.9%) had high-grade disease. Agent Orange exposure was linked with a 52% increase in overall risk of prostate cancer detection by biopsy. Exposure to the herbicide did not confer an increase in risk of low-grade prostate cancer, but was linked with a 75% increase in risk of high-grade prostate cancer. In addition, Agent Orange exposure was associated with more than a two-fold increase in the highest-grade, most lethal cancers.

This study indicates that determining menís Agent Orange exposure status is a readily identifiable means of improving prostate cancer screening for U.S. veterans, allowing for earlier detection and treatment of lethal cases and potentially prolonging survival and improving quality of life.

"It also should raise awareness about potential harms of chemical contaminants in biologic agents used in warfare and the risks associated with waste handling and other chemical processes that generate dioxin or dioxin-related compounds," Garzotto said.